1. Technical Field of the Invention
The present invention relates to a shape detecting apparatus for detecting the distribution of tensions in the lateral direction at a hot rolling line.
2. Description of the Related Art
As a means for detecting the distribution of lateral tensions at a rolling line, Patent Literatures 1 to 5 have been applied heretofore.
The “Shape control apparatus” of [Patent Literature 1] is shown in FIGS. 1A and 1B. A roller 51 is installed rotatably at the tip portion of a torsion bar 52 using a pin 53, and a pin 54 is equipped at the base portion of this torsion bar 52 and is fixed to a bracket 55. On a fixing portion 56 of the bracket 55, a strain-measuring gauge, e.g. a strain gauge 57 is attached to compose a tension detect element 58. In FIG. 1B, 59 is a lead wire to conduct an electric signal (detection signal) from strain gauge 57.
The “Shape detecting apparatus” of [Patent Literature 2] is shown in FIG. 2. Every time a roll 61 rotates by one turn, the center of a load detector 62 comes close to a location where the roll begins to contact a metal strip, then a position detector 67 outputs a command signal which is given to first and second holders 65, 66 and a delay circuit 68. Then the delay circuit 68 gives a command signal to the first holder 65 after a predetermined time from the command signal.
On the other hand, when the first holder 65 is given a command signal from the position detector 67, the holder is reset before the metal strip is applied to the load detector 62, and when a command signal is given to the holder from the delay circuit 68, the holder holds each load signal immediately before the center of the load detector comes right underneath the load.
The second holder 66 holds a peak value of detection values when the center of the load detector passes the point just below the load due to the metal strip. A calculator 69 obtains the tension of the metal strip based on load signals once held at both holders and then given to the calculator. Therefore, variations in the tension of the metal strip can precisely be determined. In FIG. 2, 63 and 64 represent an amplifier and a slip ring respectively.
The “Shape measuring roller” of [Patent Literature 3] is shown in FIG. 3. A shape measuring roller is composed of a horizontal supporting shaft 72, a rotating rotor 74, a pressure detector (not shown), a shifting device 76 and a calculating controller 78.
The rotating rotor 74 is supported rotatably on the supporting shaft 72 using air bearings and is disposed adjacently. The pressure detector detects air pressure at the inner surface of the rotor 74. The shifting device 76 moves the supporting shaft 72 in the axial direction. The calculating controller 78 calculates a width x by which both ends of rolling strip 71 respectively contact the rotating rotor and controls the shifting apparatus. When the contact width x is smaller than ½ of the width B of the rotating rotor that ends of the rolling strip come in contact with, the supporting shaft 72 is moved in the axial direction by a predetermined distance by the shifting device 76.
The “Flatness measuring roller” of [Patent Literature 4] is shown in FIGS. 4A and 4B. The roller is formed as a looper adjustable in the direction of a strip, and this looper is provided with many measuring regions that exist in parallel laterally over the entire strip. In this flatness measuring roller, the measuring region is composed of measuring rollers 89 that can cooperate with dynamic force measuring devices which can turn clockwise, and as supported rotatably. Each measuring roller 89 is supported with bearings inside a swinging housing-type lever framework 83. In FIGS. 4A and 4B, symbolic numbers are 82 for the shaft, 85 for a swing axial line, 86 for a rotating value former, 80 for a guide panel, 84 for a power introducing point, and 81 for the power measuring apparatus.
The “Rolled steel strip flatness detecting apparatus” of [Patent Literature 5] is shown in FIG. 5. The apparatus is a contact-type flatness detecting apparatus for detecting the flatness of a rolled strip at a steel strip manufacturing rolling process, using a contact load of the rolled steel strip S, applied to a divided roll 92 of a looper apparatus 90.
The apparatus incorporates a tangential-direction adjusting means 94, a load sensor impact absorbing means 96 and a pre-pressure applying means 98. The tangential-direction adjusting means 94 adjusts the divided roll 92 by turning a surface point up and down. The load sensor impact absorbing means 96 prevents an impact applied to the divided roll from being transferred to a load sensor. The pre-pressure applying means 98 fixes the load sensor, houses a base and a sensor cap that are fixed in the looper apparatus, connects mutually supporting bases that can turn around a center of a fixing shaft, and pressurizes the above-mentioned supporting bases to a base unit with a predetermined pressure.
[Patent Literature 1]
    Japanese patent official publication No. 86290, 1993[Patent Literature 2]    Japanese patent official publication No. 40038, 1994[Patent Literature 3]    Unexamined Japanese patent publication No. 137831, 1998[Patent Literature 4]    Unexamined Japanese patent publication No. 314821, 1998[Patent Literature 5]    Japanese patent publication No. 504211, 2003
However, the aforementioned conventional shape detecting apparatus involve the following problems.    (1) Normally at a hot rolling line, a looper apparatus is installed to control tensions. If a shape detecting function has to be added to an existing looper apparatus, the above-mentioned conventional shape detecting apparatus need to replace the whole equipment.    (2) Because a load cell is arranged in the looper arm, the same number of looper arms as the number of the divided rolls is required, resulting therefore in a large weight and GD2 of the entire looper, so the looper cannot quickly respond to a control command.    (3) Because of a long looper arm (lever framework length), if the width of a roll is made small, the lateral toughness thereof is lost (small tread length), the roll may deteriorate in the life or be damaged due to a lateral shifting force of a rolled plate.    (4) Because the rotation fulcrum and the dynamic force measuring point (load measuring point) of the lever framework are exposed, the equipment might be subject to aging and aggravation in measuring accuracy in an adverse environment.    (5) If the width of a rolled plate is less than one half of the roll width, the shape measuring roll may tilt by a moment acting, and detection accuracy become lower.    (6) The inner periphery and the bearing of the measuring roll directly contact each other, so heat can be easily transferred from outside the roll, resulting in deterioration of bearing life or damage thereof due to a temperature rise.    (7) Because a measuring roll corresponds to a load cell, if a load cell fails, measurements stop.    (8) A measuring roll contacts a rolled plate and is driven by the material. If the roll is quickly accelerated from a stopped state, it may slip and flaws the rolled plate and make unevenly wearing the roll. Once an uneven wear is produced, it is quickly accelerated, and the roll soon becomes unrotatable. Also, unless the roll is rotating, the roll is cooled unevenly with cooling water, resulting in uneven distribution of temperatures on each part of the roll, so the roll may deform and the aforementioned problems occur.    (9) The measuring system can be affected easily by temperatures of a rolled plate, therefore, a measurement error may be caused because of temperature variations.